1. Field of the Invention
The present invention relates generally to seats for people in all types of seating applications, such as in markets for the home, office, and medicine (such as wheelchairs) and private, industrial, and military vehicles and aircraft. The present invention relates more particularly to a seat with biomechanical articulation for a person seated in the seat.
2. Description of the Related Art
Today, seats for people typically have a seat portion and a back portion which may be adjustable relative to each other. Generally, the seat portion and back portion are rigid. These seats do not provide geometric compatibility and movement capability between a person's body and the seat that accommodate changes of spinal curvature, torso recline angle and leg position. Geometrical compatibility between the person's body and seat and an ability to move are essential for comfort. If there is geometric interference between the body and seat in any position that a person may choose, then that person will not be comfortable.
One attempt to provide a seat with geometric compatibility is by incorporating a floating lumbar. An example of a seat with a floating lumbar is disclosed in U.S. Patent No. 4,832,401 to Brooks. This patented seat has a seat back joined to a seat cushion frame via a floor and two generally parallel spaced apart frame members. The patented seat also has a lumbar support resiliently, slidably and pivotally connected to the frame members. When a person sits in the patented seat, a femur seating surface deflects downward which causes the lumbar support to be pulled downward against the action of a spring to assure a fit to the spine of the seated person.
One disadvantage of the above patented seat is that it lacks sufficient articulation to move with and support a person's body. Another disadvantage of the patented seat is that it is not geometrically compatible with the person's body shape as the person's body is positioned in different postures.